Trace removal of benzene vapour using double-walled metal-dipyrazolate frameworks.

In principle, porous physisorbents are attractive candidates for the removal of volatile organic compounds such as benzene by virtue of their low energy for the capture and release of this pollutant. Unfortunately, many physisorbents exhibit weak sorbate-sorbent interactions, resulting in poor selectivity and low uptake when volatile organic compounds are present at trace concentrations. Herein, we report that a family of double-walled metal-dipyrazolate frameworks, BUT-53 to BUT-58, exhibit benzene uptakes at 298 K of 2.47-3.28 mmol g-1 at <10 Pa. Breakthrough experiments revealed that BUT-55, a supramolecular isomer of the metal-organic framework Co(BDP) (H2BDP = 1,4-di(1H-pyrazol-4-yl)benzene), captures trace levels of benzene, producing an air stream with benzene content below acceptable limits. Furthermore, BUT-55 can be regenerated with mild heating. Insight into the performance of BUT-55 comes from the crystal structure of the benzene-loaded phase (C6H6@BUT-55) and density functional theory calculations, which reveal that C-H···X interactions drive the tight binding of benzene. Our results demonstrate that BUT-55 is a recyclable physisorbent that exhibits high affinity and adsorption capacity towards benzene, making it a candidate for environmental remediation of benzene-contaminated gas mixtures.

Effects of urban sprawl on arthropod communities in peri-urban farmed landscape in Shenbei New District, Shenyang, Liaoning Province, China.

Peri-urban farmland provides a diversity of ecological services. However, it is experiencing increasing pressures from urban sprawl. While the effects of land use associated with farming on arthropod assemblages has received increasing attention, most of this research has been conducted by comparing conventional and organic cropping systems. The present study identifies the effects of urban sprawl and the role of non-cropped habitat in defining arthropod diversity in peri-urban farmed landscapes. Multi-scale arthropod data from 30 sampling plots were used with linear-mixed models to elucidate the effects of distance from urban areas (0-13 km; 13-25 km and >25 km, zones I, II, and III, respectively) on arthropods. Results showed that urban sprawl, disturbed farm landscapes, and disturbance in non-cropped habitats had negative effects on arthropods, the latter requiring arthropods to re-establish annually from surrounding landscapes via dispersal. While arthropod species richness showed no obvious changes, arthropod abundance was lowest in zone II. Generally, patch density (PD), Shannon diversity index (SHDI), and aggregate index (AI) of non-cropped habitat were major drivers of changes in arthropod populations. This study contributes to identifying the effects of urban sprawl on arthropod diversity and documenting the multiple functions of farm landscapes in peri-urban regions.

[Cooperative relations between non-cropped habitats and soil animals in suburban farmland Landscape: A case in Shenbei New District in Shenyang, China].

Non-cropped habitat in farm landscape plays a significant role in biodiversity, the functions of arable land and crop yields. This study focused on Shenbei New District in Shenyang City of Liaoning Province in Northeast China, which was a typical area with contradiction between biodiversity conservation and the high demand of agricultural production in the process of urbanization. Information entropy model, hand-picking and Baermann method were used for survey and identification of arthropods and nematodes in soils in urban suburban (US), urban fringe area (UFA) and rural area ( RA). The cooperative relations between the number of soil animals and types, structure as well as the total amount of non-cropped habitat were investigated in these three types of areas using linear regression. Our results showed that the area of single patch in non-cropped habitat was smaller than one hectare in Shenbei New District, and the types and the proportion of non-cropped habitat patches were increasing along with the increase of their distance to the urban center. But the proportion of non-cropped habitats areas appeared under an inverted U-type change. The proportion of non-cropped habitat patches was from 8.6% to 27.8%. The individual number of soil animals showed the U-type trend, while their species number changed irregularly. The individual number of soil animals increased with the increase of the proportion of non-cropped habitat patches in RA and US. There was no obvious correlation between the individual number of soil animal and the proportion of non-cropped habitat patches in UFA. The individual number of soil animals decreased with the increase of the proportion of non-cropped habitats areas. There was no cooperative relation in the proportion of non-cropped habitats and the number of soil animal species.